Calendaring Extensions to WebDAV (CalDAV)cyrus@daboo.nameOracle Corporation600 Blvd. de Maisonneuve WestSuite 1900MontrealQCH3A 3J2CAbernard.desruisseaux@oracle.comhttp://www.oracle.com/
Open Source Application Foundation
2064 Edgewood Dr.Palo AltoCA94303USlisa@osafoundation.orghttp://www.osafoundation.org/
Applications
calschedcalschcaldavcalendarcalendaringschedulingwebdaviCaliCalendartext/calendarHTTP
This document specifies a set of methods, headers, message bodies,
properties, and reports that define calendar access extensions to
the WebDAV protocol. The new protocol elements are intended to make
WebDAV-based calendaring and scheduling an interoperable standard
that supports calendar access, calendar management, calendar sharing,
and calendar publishing.
The concept of using HTTP and
WebDAV as a basis for a calendar
access protocol is by no means a new concept: it was discussed in
the IETF CALSCH working group as early as 1997 or 1998. Several
companies have implemented calendar access protocols using HTTP
to upload and download iCalendar
objects, and using WebDAV to get listings of resources.
However, those implementations do not interoperate because there
are many small and big decisions to be made in how to model
calendaring data as WebDAV resources, as well as how to implement
required features that aren't already part of WebDAV.
This document proposes a way to model calendar data in WebDAV,
with additional features to make an interoperable calendar
access protocol.
Discussion of this Internet-Draft is taking place on the mailing list
<http://lists.osafoundation.org/mailman/listinfo/ietf-caldav>.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" in this document are to be interpreted as
described in .
The term "protected" is used in the Conformance field
of property definitions as defined in Section 1.4.2 of
.
When XML element types in the namespaces "DAV:" and
"urn:ietf:params:xml:ns:caldav" are referenced in this
document outside of the context of an XML fragment,
the string "DAV:" and "CALDAV:" will be prefixed to
the element type names respectively.
Definitions of XML elements in this document use XML element
type declarations (as found in XML Document Type Declarations),
described in Section 3.2 of .
The namespace "urn:ietf:params:xml:ns:caldav" is reserved
for the XML elements defined in this specification, its
revisions, and related CalDAV specifications. XML elements
defined by individual implementations MUST NOT use the
"urn:ietf:params:xml:ns:caldav" namespace, and instead
should use a namespace that they control.
The XML declarations used in this document do not include
namespace information. Thus, implementers MUST NOT use
these declarations as the only way to create valid CalDAV
properties or to validate CalDAV XML element type. Some of
the declarations refer to XML elements defined by
WebDAV which use the "DAV:"
namespace. Wherever such XML elements appear, they are
explicitly prefixed with "DAV:" to avoid confusion.
Also note that some CalDAV XML element names are identical to
WebDAV XML element names, though their namespace differs. Care
must be taken not to confuse the two sets of names.
A "precondition" of a method describes the state of the
server that must be true for that method to be performed.
A "postcondition" of a method describes the state of the
server that must be true after that method has been completed.
If a method precondition or postcondition for a request is
not satisfied, the response status of the request MUST be
either 403 (Forbidden) if the request should not be repeated
because it will always fail, or 409 (Conflict) if it is
expected that the user might be able to resolve the conflict
and resubmit the request.
In order to allow better client handling of 403 and 409
responses, a distinct XML element type is associated with
each method precondition and postcondition of a request.
When a particular precondition is not satisfied or a
particular postcondition cannot be achieved, the appropriate
XML element MUST be returned as the child of a top-level
DAV:error element in the response body, unless otherwise
negotiated by the request. In a 207 Multi-Status response,
the DAV:error element would appear in the appropriate
DAV:responsedescription element.
This section lists what functionality is required of a CalDAV
server. To advertise support for CalDAV, a server:
MUST support iCalendar as a
media type for calendar object resource format;
MUST support WebDAV Class 1;
MUST support WebDAV ACL with
the additional privilege defined in
of this document;
MUST support transport over TLS
as defined in ;
MUST support ETags with additional
requirements specified in of
this document;
MUST support all calendaring REPORTs defined in
of this document; and
MUST advertise support on all calendar collections and
calendar object resources for the calendaring REPORTs
in the DAV:supported-report-set property as defined in
Versioning Extensions to WebDAV.
In addition, a server:
SHOULD support the MKCALENDAR method defined in
of this document.
One of the features which has made WebDAV a successful protocol
is its firm data model. This makes it a useful framework for
other applications such as calendaring. This specification
follows the same pattern by developing all features based
on a well-described data model.
As a brief overview, a CalDAV calendar is modelled as a WebDAV
collection with defined structure; each calendar collection contains
a number of resources representing calendar objects as its direct
child resource. Each resource representing a calendar object (event
or to-do, or journal entry, or other calendar components) is called
a "calendar object resource". Each calendar object resource and each
calendar collection can be individually locked and have individual
WebDAV properties. Requirements derived from this model are provided
in and
.
A CalDAV server is a calendaring-aware engine combined with
a WebDAV repository. A WebDAV repository is a set of WebDAV
collections, containing other WebDAV resources, within a
unified URL namespace. For example, the repository
"http://www.example.com/webdav/" may contain WebDAV
collections and resources, all of which have URLs beginning
with "http://www.example.com/webdav/". Note that the root
URL "http://www.example.com/" may not itself be a WebDAV
repository (for example, if the WebDAV support is implemented
through a servlet or other Web server extension).
A WebDAV repository MAY include calendar data in some parts
of its URL namespace, and non-calendaring data in other parts.
A WebDAV repository can advertise itself as a CalDAV server
if it supports the functionality defined in this
specification at any point within the root of the
repository. That might mean that calendaring data is spread
throughout the repository and mixed with non-calendar data
in nearby collections (e.g., calendar data may be found in
/home/lisa/calendars/ as well as in /home/bernard/calendars/,
and non-calendar data in /home/lisa/contacts/). Or, it might
mean that calendar data can be found only in certain sections of
the repository (e.g., /calendar/). Calendaring
features are only required in the repository sections that
are or contain calendar object resources. So a repository
confining calendar data to the /calendar/ collection would
only need to support the CalDAV required features within
that collection.
The CalDAV server or repository is the canonical location
for calendar data and state information. Both CalDAV
servers and clients MUST ensure that the data is consistent
and compliant. Clients may submit requests to change data
or download data. Clients may store calendar objects
offline and attempt to synchronize at a later time.
However, clients MUST be prepared for calendar data on the
server to change between the time of last synchronization
and when attempting an update, as calendar collections may
be shared and accessible via multiple clients. Entity tags
and other features make this possible.
Recurrence is an important part of the data model because it
governs how many resources are expected to exist. This
specification models a recurring calendar component and its
recurrence exceptions as a single resource. In this model,
recurrence rules, recurrence dates, exception rules, and
exception dates are all part of the data in a single
calendar object resource. This model avoids problems of limiting
how many recurrence instances to store in the repository, how to
keep recurrence instances in sync with the recurring calendar
component,
and how to link recurrence exceptions with the recurring calendar
component. It also results in less data to synchronize between
client and server, and makes it easier to make changes to all
recurrence instances or to a recurrence rule. It makes it
easier to create a recurring calendar component, and easier
to delete all recurrence instances.
Clients are not forced to retrieve information about all recurrence
instances of a recurring component. The CALDAV:calendar-query and
CALDAV:calendar-multiget REPORTs defined in this document allow
clients to retrieve only recurrence instances that overlap a
given time range.
Calendar object resources contained in calendar collections MUST
NOT contain more than one type of calendar component (e.g., VEVENT,
VTODO, VJOURNAL, VFREEBUSY, etc.) with the exception of VTIMEZONE
components which MUST be specified for each unique TZID parameter
value specified in the iCalendar object. For instance, a calendar
object resource can contain two VEVENT components and one VTIMEZONE
component, but it cannot contain one VEVENT component and one VTODO
component.
Calendar object resources contained in calendar collections MUST
NOT specify the iCalendar METHOD property.
The UID property value of the calendar components contained in a
calendar object resource MUST be unique in the scope of the
calendar collection.
Calendar components in a calendar collection that have
different UID property values MUST be stored in separate calendar
object resources.
Calendar components with the same UID property value, in a given
calendar collection, MUST be contained in the same calendar object
resource. This ensures that all components in a recurrence "set"
are contained in the same calendar object resource. In that case there
will be one component without a RECURRENCE-ID property (the
component that defines the recurrence pattern) and all the rest
will have that property (these are the recurrence exceptions).For example, given the following iCalendar object:
The VEVENT component with the UID value "1@example.com", would
be stored in its own calendar object resource. The two
VEVENT components with the UID value "2@example.com", which
represent a recurring event where one recurrence instance has
been overridden, would be stored in the same calendar object
resource.
A calendar collection contains calendar object resources that
represent calendar components within a calendar. A calendar
collection is manifested to clients as a WebDAV resource
collection identified by a URL. A calendar collection MUST
report the DAV:collection and CALDAV:calendar XML elements
in the value of the DAV:resourcetype property. The element
type declaration for CALDAV:calendar is:
A calendar collection can be created through provisioning (e.g.,
automatically created when a user's account is provisioned),
or it can be created with the MKCALENDAR method (see
). This method can be useful
for a user to create a second calendar (e.g., soccer
schedule) or for users to share a calendar (e.g., team
events or conference room). Note however that this document
doesn't define what extra calendar collections are for.
Users must rely on non-standard cues to find out what a
calendar collection is for, or use the
CALDAV:calendar-description property defined
in to provide such a
cue.
Calendar collections MUST only contain calendar object
resources and collections that are not calendar collections.
Furthermore, collections contained in calendar collections
MUST NOT contain calendar collections. This specification
does not define how collections contained in calendar
collections are used and may relate to the calendar object
resources contained in the calendar collections.
Multiple calendar collections MAY be children of the same
collection.
A server supporting the features described in this document MUST
include "calendar-access" as a field in the DAV response header
from an OPTIONS request on any resource that supports any
calendar properties, reports, method, or privilege. A value of
"calendar-access" in the DAV response header MUST indicate that
the server supports all MUST level requirements specified in this
document.
In this example, the OPTIONS method returns the value
"calendar-access" in the DAV response header to
indicate that the collection "/home/bernard/calendars/"
may support properties, reports, methods, or privilege
defined in this specification.
This section defines properties that MAY be defined
on calendar collections.
calendar-description
urn:ietf:params:xml:ns:caldav
Provides a human-readable description of the calendar
collection.
This property MAY be protected and SHOULD NOT be returned
by a PROPFIND allprop request (as defined in Section 12.14.1
of ). An xml:lang attribute
indicating the human language of the description SHOULD
be set for this property by clients or through server
provisioning. Servers MUST return any xml:lang attribute
if set for the property.
The CALDAV:calendar-description property MAY be defined on
any calendar collection. If present, the property contains
a description of the calendar collection that is suitable
for presentation to a user.
calendar-timezone
urn:ietf:params:xml:ns:caldav
Specifies a time zone on a calendar collection.
This property SHOULD NOT be returned by a PROPFIND
allprop request (as defined in Section 12.14.1 of
).
The CALDAV:calendar-timezone property SHOULD be defined
on all calendar collections to specify the time zone the
server should rely on to resolve "date" values and
"date with local time" values (i.e., floating time)
to "date with UTC time" values. The server will require
this information to determine if a calendar component
scheduled with "date" values or "date with local time"
values overlaps a CALDAV:time-range specified in a
CALDAV:calendar-query REPORT. The server will also
require this information to compute the proper FREEBUSY
time period as "date with UTC time" in the VFREEBUSY
component returned in a response to a CALDAV:free-busy-query
REPORT request that takes into account calendar components
scheduled with "date" values or "date with local time"
values.
supported-calendar-component-set
urn:ietf:params:xml:ns:caldav
Specifies the type of calendar component types
(e.g., VEVENT, VTODO, etc.) that calendar object
resources may contain in the calendar collection.
This property MUST be protected and SHOULD NOT be returned
by a PROPFIND allprop request (as defined in Section 12.14.1
of ).
The CALDAV:supported-calendar-component-set property
MAY be defined on any calendar collection to specify
restrictions on the calendar component types that calendar
object resources may contain in a calendar collection.
Since this property is protected it cannot be changed by
clients using a PROPPATCH request. However, clients can
initialize the value of this property when
creating a new calendar collection with MKCALENDAR.
The empty-element tag <C:comp name="VTIMEZONE"/>
MUST only be specified if support for calendar object
resources that only contain VTIMEZONE components is
provided or desired. Support for VTIMEZONE components
in calendar object resources that contain VEVENT or
VTODO components is always assumed.
supported-calendar-data
urn:ietf:params:xml:ns:caldav
Specifies restrictions on a
calendar collection.
This property MUST be protected and SHOULD NOT be returned
by a PROPFIND allprop request (as defined in Section 12.14.1
of ).
The CALDAV:supported-calendar-data property MAY be defined
on any calendar collection to specify the media type
supported for the calendar object resources contained in
a given calendar collection (e.g., iCalendar version 2.0).
The creation of calendar collections and calendar object resources may
be initiated by either a CalDAV client or by the CalDAV server. For
example, a server might come preconfigured with a user's calendar
collection, or the CalDAV client might request the server to create a
new calendar collection for a given user. Servers might populate
events as calendar objects inside a calendar collection, or clients
might request the server to create events. Either way, both client and
server MUST comply with the requirements in this document, and MUST
understand objects appearing in calendar collections or according to
the data model defined here.
An HTTP request using the MKCALENDAR method creates a new calendar
collection resource. A server MAY restrict calendar collection
creation to particular collections.
Support for MKCALENDAR on the server is only RECOMMENDED and not
REQUIRED because some calendar stores only support one calendar
per user (or principal) and those are typically pre-created for
each account. However, servers and clients are strongly encouraged
to support MKCALENDAR whenever possible to allow users to create
multiple calendar collections to better help organize their data.
Clients SHOULD use the DAV:displayname property for a
human-readable name of the calendar. Clients can either
specify the value of the DAV:displayname property in the
request body of the MKCALENDAR request, or alternatively
issue a PROPPATCH request to change the DAV:displayname property
to the appropriate value immediately after issuing the
MKCALENDAR request. Clients SHOULD NOT set the DAV:displayname
property to be the same as any other calendar collection at the same
URI "level". When displaying calendar collections to users,
clients SHOULD check the DAV:displayname property and use that
value as the name of the calendar. In the event that the
DAV:displayname property is empty, the client MAY use the last
part of the calendar collection URI as the name.
If a MKCALENDAR request fails, the server state preceding the
request MUST be restored.
Marshalling:
If a request body is included, it MUST be a CALDAV:mkcalendar
XML element. Instruction processing MUST occur in the order
instructions are received (i.e., from top to bottom).
Instructions MUST either all be executed or none executed.
Thus if any error occurs during processing all executed
instructions MUST be undone and a proper error result
returned. Instruction processing details can be found in
the definition of the DAV:set instruction in section 12.13
of .
If a response body for a successful request is included, it MUST
be a CALDAV:mkcalendar-response XML element.
The response MUST include a Cache-Control:no-cache header.
Preconditions:
(DAV:resource-must-be-null): A resource MUST NOT exist
at the Request-URI;
(CALDAV:calendar-collection-location-ok): The
Request-URI MUST identify a location where a calendar
collection can be created; and
(DAV:needs-privilege): The DAV:bind privilege MUST be
granted to the current user on the parent collection
of the Request-URI.
Postconditions:
(CALDAV:initialize-calendar-collection): A new
calendar collection exists at the Request-URI. The
DAV:resourcetype of the calendar collection MUST
contain both DAV:collection and CALDAV:calendar XML
elements.
The following are examples of response codes one would expect
to get in a response to a MKCALENDAR request. Note that this
list is by no mean exhaustive.
201 (Created) - The calendar collection resource was created
in its entirety;
207 (Multi-Status) - The calendar collection resource was
not created since one or more DAV:set instructions specified
in the request body could not be processed successfully. The
following are examples of response codes one would expect
to be used in a 207 (Multi-Status) response in this situtation:
403 (Forbidden) - The client, for reasons the server
chooses not to specify, cannot alter one of the properties;
409 (Conflict) - The client has provided a value whose
semantics are not appropriate for the property. This
includes trying to set read-only properties;
424 (Failed Dependency) - The DAV:set instruction on the
specified resource would have succeeded if it were not for
the failure of another DAV:set instruction specified in the
request body;
423 (Locked) - The specified resource is locked and the
client either is not a lock owner or the lock type
requires a lock token to be submitted and the client did
not submit it; and
507 (Insufficient Storage) - The server did not have
sufficient space to record the property;
403 (Forbidden) - This indicates at least one of two
conditions: 1) the server does not allow the creation of calendar
collections at the given location in its namespace, or 2) the
parent collection of the Request-URI exists but cannot accept
members;
405 (Method Not Allowed) - MKCALENDAR can only be executed
on a null resource;
409 (Conflict) - A collection cannot be made at the
Request-URI until one or more intermediate collections have been
created;
415 (Unsupported Media Type) - The server does not support
the request type of the body; and
507 (Insufficient Storage) - The resource does not have
sufficient space to record the state of the resource after the
execution of this method.
This example creates a calendar collection called
/home/lisa/calendars/events/ on the server
cal.example.com with specific values for the properties
DAV:displayname, CALDAV:calendar-description,
CALDAV:supported-calendar-component-set, and
CALDAV:calendar-timezone.
Clients populate calendar collections with calendar object
resources. The URL for each calendar object resource is
entirely arbitrary, and does not need to bear a specific
relationship to the calendar object resource's iCalendar
properties (e.g., SUMMARY, UID, DTSTART, etc.) or other
metadata. New calendar object resources MUST be created
with a PUT request targeted at an unmapped URI. A PUT
request targeted at mapped URI updates an existing calendar
object resource.
When servers create new resources, it's not hard for the server to
choose an unmapped URI. It's slightly tougher for clients, because a
client might not want to examine all resources in the collection,
and might not want to lock the entire collection to ensure that a new
resource isn't created with a name collision. However, there is an HTTP
feature to mitigate this. If the client intends to create a new
non-collection resource, such as a new VEVENT, the client SHOULD
use the HTTP request header "If-None-Match: *" on the PUT request.
The Request-URI on the PUT request MUST include the target
collection, where the resource is to be created, plus the name of
the resource in the last path segment. The last path segment could
be a random number, or it could be a sequence number, or a string
related to the calendar object resource's UID property.
The "If-None-Match: *" request header ensures that the client will
not inadvertently overwrite an existing resource.
The request to change an existing event is the same, but with a
specific ETag in the "If-Match" header, rather than the
"If-None-Match" header.
As indicated in Section 3.10 of
, the URL of calendar
object resources containing (an arbitrary set of) calendaring
and scheduling information may be suffixed by ".ics", and the URL
of calendar object resources containing free or busy time
information may be suffixed by ".ifb".
Additional Preconditions for PUT within calendar collections:
(CALDAV:supported-calendar-data): The resource submitted in
the PUT request MUST be a supported media type (e.g.,
iCalendar) for calendar object resources;
(CALDAV:valid-calendar-data): The resource submitted in the
PUT request MUST comply to the specified media type
specification (e.g., iCalendar);
(CALDAV:valid-calendar-object-resource): The resource
submitted in the PUT request MUST obey all restrictions
specified in
(e.g., calendar object resources MUST NOT contain more
than one type of calendar component, calendar object
resources MUST NOT specify the iCalendar METHOD property
etc.);
(CALDAV:supported-calendar-component): The resource
submitted in the PUT request MUST contain a type of
calendar component that is supported in the targeted calendar
collection; and
(CALDAV:no-uid-conflict): The resource submitted in the
PUT request MUST NOT specify an iCalendar UID property
value already in use in the targeted calendar collection
or overwrite an existing calendar object resource with
a calendar object resource that has a different UID
property value.
The DAV:getetag property MUST be defined on all calendar
object resources.
A response to a GET request targeted at a calendar object
resource MUST contain an ETag response header field
indicating the current value of the entity tag of the
calendar object resource.
A response to a PUT request MAY contain an ETag response header
field indicating the current value of the entity tag for the
calendar object resource just created.
A response to a PUT request with a strong entity tag MUST mean
that the server will return on a subsequent GET request a calendar
object resource that is equivalent by octet equality.
A response to a PUT request with a weak entity tag MUST mean that
the server will return on a subsequent GET request a calendar
object resource that is equivalent and could be substituted for
the submitted calendar object resource with no significant change
in semantics.
A response to a PUT request MUST NOT contain an ETag response
header field if the server will return on a subsequent GET
request a calendar object resource that has significant change
in semantics compared to the submitted calendar object resource.
In this case, the client SHOULD retrieve the new entity (and
ETag) as a basis for further changes, rather than use the entity
it had sent with the PUT request.
CalDAV servers MUST support and adhere to the requirements of
WebDAV ACL. WebDAV ACL provides
a framework for an extensible set of privileges that can be
applied to WebDAV collections and ordinary resources.
CalDAV servers MUST also support the calendaring privilege
defined in this section.
Calendar users often wish to allow other users to see their
busy time information, without viewing the other details
of the calendar components (location, summary, attendees).
This allows a significant amount of privacy while still
allowing other users to schedule meetings at times when
the user is likely to be free.
The CALDAV:read-free-busy privilege controls which calendar
collections and calendar object resources are examined when
a CALDAV:free-busy-query REPORT request is processed (see
). This privilege can be
granted on calendar collections or calendar object resources.
Servers MUST support this privilege on all calendar collections
and calendar object resources.
The CALDAV:read-free-busy privilege MUST be aggregated in the
DAV:read privilege. Servers MUST allow the CALDAV:read-free-busy
to be granted without the DAV:read privilege being granted.
Clients should note that when only the CALDAV:read-free-busy
privilege has been granted on a resource, this does not imply
access to GET, HEAD, OPTIONS and PROPFIND on the resource --
those operations are governed by the DAV:read privilege.
This section defines an additional property for WebDAV principal
resources as defined in .
calendar-home-set
urn:ietf:params:xml:ns:caldav
Identifies the URL of any WebDAV collections that contain
calendar collections owned by the associated principal
resource.
This property MAY be protected and SHOULD NOT be returned
by a PROPFIND allprop request (as defined in Section 12.14.1
of ).
Support for this property is RECOMMENDED.
The CALDAV:calendar-home-set property is meant to allow
users to easily find the calendar collections owned by
the principal. Typically, users will group all the
calendar collections that they own under a common
collection. This property specify the URL of
collections that either are calendar collections or
ordinary collections that have child or descendant
calendar collections owned by the principal.
This section defines the REPORTs that CalDAV servers MUST
support on calendar collections and calendar object resources.
CalDAV servers MUST advertise support for these REPORTs
on all calendar collections and calendar object resources
with the DAV:supported-report-set property defined in
Section 3.1.5 of . CalDAV servers
MAY also advertise support for these REPORTs on ordinary
collections.
Some of these REPORTs allow calendar data (from possibly
multiple resources) to be returned.
The REPORT method (defined in Section 3.6 of
) provides an
extensible mechanism for obtaining information about one or
more resources. Unlike the PROPFIND method, which returns
the value of one or more named properties, the REPORT method
can involve more complex processing. REPORT is valuable in
cases where the server has access to all of the information
needed to perform the complex request (such as a query), and
where it would require multiple requests for the client to
retrieve the information needed to perform the same request.
CalDAV servers MUST support the DAV:expand-property REPORT
defined in Section 3.8 of .
Servers MAY support the REPORTs defined in this document
on ordinary collections, that is, collections that are not
calendar collections. In computing responses to the REPORTs
defined in this document, servers MUST only consider calendar
object resources contained in calendar collections, subject
also to the value of the Depth request header.
iCalendar provides a way to specify DATE and DATE-TIME values
that are not bound to any time zone in particular, hereafter
called "floating date" and "floating time" respectively. These
values are used to represent the same day, hour, minute and
second value regardless of which time zone is being observed.
For instance, the DATE value "20051111", represents November 11th,
2005 in no specific time zone, while the DATE-TIME value
"20051111T111100" represents November 11th, 2005 at 11:11 AM in
no specific time zone.
CalDAV servers may need to convert "floating date" and "floating
time" values in date with UTC time values in the processing
of calendaring REPORT requests.
For the CALDAV:calendar-query REPORT, CalDAV servers MUST rely
on the value of the CALDAV:timezone XML element, if specified
as part of the request body, to perform the proper conversion
of "floating date" and "floating time" values to date with UTC
time values. If the CALDAV:timezone XML element is not specified
in the request body, CalDAV servers MUST rely on the value of
the CALDAV:calendar-timezone property, if defined, else the
CalDAV servers MAY rely on the time zone of their choice.
For the CALDAV:free-busy-query REPORT, CalDAV servers MUST rely
on the value of the CALDAV:calendar-timezone property, if defined,
to compute the proper FREEBUSY time period value as date with UTC
time, for calendar components scheduled with "floating date" or
"floating time". If the CALDAV:calendar-timezone property is not
defined, CalDAV servers MAY rely on the time zone of their choice.
Some of the reports defined in this section can be targeted at
calendar object resources within a specific time range. To
determine whether a calendar object resource matches the time
range filter element, the start and end times for the particular
type of object are determined and then compared to the requested
time range. If the start and end overlap the requested time
range, then the calendar object resource matches the filter
element. The rules defined in
for determining the actual start and end times of calendar
components MUST be used, along with the rules for determining
overlap specified in of this
document.
When such time range filtering is used, special consideration must
be given to recurring calendar components such as VEVENT and
VTODO components. The server MUST expand recurring components to
determine whether any recurrence instances overlap the specified
time range. If one or more recurrence instances overlap the time
range, then the calendar object resource matches the filter element.
In addition, CalDAV provides three ways to determine which
components of a calendar object resource are returned
from the recurrence set. The three options are:
Return all the calendar components contained in the calendar
object resources. This includes the component that defines
the recurrence set, referred to as the "master component",
as well as the components that define exceptions to the
recurrence set, referred to as the "overridden components".
According to the rules defined in
all recurrence instances of a recurring component will
always be contained in the same calendar object resource.
Return the "master component" and only the "overridden
components" that currently or originally overlap the
specified time range. This avoids the need for clients
to process "overridden components" outside of the time
range they are interested in.
See .
Return "expanded" calendar components that represent only
those recurrence instances in the recurrence set that
overlap the specified time range. This avoids the need for
clients to do any recurrence processing themselves as the
server does the expansion for them and provides the list of
instances. See .
The CALDAV:calendar-query REPORT performs a search for all
calendar object resources that match a specified filter.
The response of this REPORT will contain all the WebDAV
properties and calendar object resource data specified in the
request. In the case of the CALDAV:calendar-data XML element,
one can explicitly specify the calendar components and properties
that should be returned in the calendar object resource data
that matches the filter.
The format of this REPORT is modeled on the PROPFIND method.
The request and response bodies of the CALDAV:calendar-query
REPORT use XML elements that are also used by PROPFIND. In
particular the request can include XML elements to request
WebDAV properties to be returned. When that occurs the
response should follow the same behavior as PROPFIND with
respect to the DAV:multistatus response elements used to
return specific property results. For instance, a request
to retrieve the value of a property which does not exist
is an error and MUST be noted with a response XML element
which contains a 404 (Not Found) status value.
Support for the CALDAV:calendar-query REPORT is REQUIRED.
Marshalling:
The request body MUST be a CALDAV:calendar-query XML
element as defined in .
The response body for a successful request MUST be a
DAV:multistatus XML element (i.e., the response uses the
same format as the response for PROPFIND). In the case
where there are no response elements, the returned
DAV:multistatus XML element is empty.
The response body for a successful CALDAV:calendar-query
REPORT request MUST contain a DAV:response element
for each iCalendar object that matched the search
filter. Calendar data is being returned in the
CALDAV:calendar-data XML element inside the
DAV:propstat XML element.
Preconditions:
(CALDAV:supported-calendar-data): The attributes
"content-type" and "version" of the CALDAV:calendar-data
XML elements specify a media type supported by the server
for calendar object resources.
(CALDAV:valid-filter): The CALDAV:filter XML element
specified in the REPORT request MUST be valid.
For instance, a CALDAV:filter cannot nest a
]]> element in a
]]> element, or a
CALDAV:filter cannot nest a
]]>
element in a
]]> element.
Postconditions:
(DAV:number-of-matches-within-limits): The number of matching
calendar object resources must fall within server-specific,
predefined limits. For example, this condition might be
triggered if a search specification would cause the return
of an extremely large number of responses.
In this example, the client requests the server to
return specific components and properties of the VEVENT
components that overlap the time range from September
2nd, 2004 at 00:00:00 am UTC to September 3rd, 2004 at
00:00:00 am UTC. In addition the DAV:getetag
property is also requested and returned as part of the
response. Note that the third calendar object returned is a
recurring event whose first instance lies outside of the requested
time range, but whose second instance does overlap the time range.
Note also that there are no restrictions on what part of the calendar
data to return, thus the server will return all components and and
properties.
In this example, the client requests the server to
return VEVENT components that overlap the time range
from June 1st, 2005 at 00:00:00 am UTC to June 9th, 2005
at 00:00:00 am UTC. Use of the CALDAV:limit-recurrence-set
element causes the server to only return overridden
recurrence instances that overlap the time range specified
in that element.
Assuming that only the following recurring VEVENT components
contains recurrence instances scheduled to overlap the
specified time range:
The server will omit the calendar component
describing the recurrence instance scheduled on June 15, 2005
in its response to the client.
In this example, the client requests the server to
return VEVENT components that overlap the time range
from June 1st, 2005 at 00:00:00 am UTC to June 9th, 2005
at 00:00:00 am UTC and to return recurring calendar
components expanded into individual recurrence instance
calendar components. Use of the CALDAV:expand
element causes the server to only return overridden recurrence
instances that overlap the time range specified in that element.
Assuming that only the following recurring VEVENT components
contains recurrence instances scheduled to overlap the
specified time range:
The server will return the recurring calendar component
expanded into two recurrence instances omitting the
recurrence instance scheduled on June 15, 2005 given
that it does not overlap the specified time range for
the expansion of the recurrence set.
In this example, the client request the server to
return the VFREEBUSY components that have free busy
information that overlap the time range from June 1st,
2005 at 00:00:00 am UTC (inclusively) to June 9th, 2005
at 00:00:00 am UTC (exclusively). Use of the
CALDAV:limit-freebusy-set element causes the server
to only return the FREEBUSY property values that
overlap the time range specified in that element.
Note that this is not an example of discovering when
the calendar owner is busy (the CALDAV:free-busy-query
REPORT is used for that purpose, combining VEVENT busy
times as well as VFREEBUSY blocks of time).
In this example, the client requests the server to
return the VTODO components that have an alarm trigger
scheduled in the specified time range. In this example, the client requests the server to
return the VEVENT component that has the UID property
set to "20041121-FEEBDAED@foo.org". In this example, the client requests the server to
return the VEVENT components that have the ATTENDEE
property with the value "mailto:bernard@example.com" and
for which the PARTSTAT parameter is set to
"NEEDS-ACTION". In this example, the client requests the server to
return all VEVENT components.
The CALDAV:calendar-multiget REPORT is used to retrieve specific
calendar object resources from within a collection, if the
Request-URI is a collection, or to retrieve a specific
calendar object resource, if the Request-URI is a calendar
object resource. This REPORT is similar to the CALDAV:calendar-query
REPORT (see ), except that it takes
a list of DAV:href elements instead of a CALDAV:filter element to
determine which calendar object resources to return.
Support for the calendar-multiget REPORT is REQUIRED.
Marshalling:
The request body MUST be a CALDAV:calendar-multiget XML
element (see ).
If the Request-URI is a collection resource, then the DAV:href
elements MUST refer to resources within that collection,
and they MAY refer to resources at any depth within the
collection. As a result the "Depth" header MUST be ignored
by the server and SHOULD NOT be sent by the client.
If the Request-URI refers to a non-collection resource,
then there MUST be a single DAV:href element that is
equivalent to the Request-URI.
The response body for a successful request MUST be a
DAV:multistatus XML element. In the case where there are no
response elements, the returned DAV:multistatus XML element
is empty.
The response body for a successful CALDAV:calendar-multiget
REPORT request MUST contain a DAV:response element
for each calendar object resource referenced by the
provided set of DAV:href elements. Calendar data is
being returned in the CALDAV:calendar-data element
inside the DAV:prop element.
In the case of an error accessing any of the provided
DAV:href resources, the server MUST return the appropriate
error status code in the DAV:status element of the
corresponding DAV:response element.
Preconditions:
(CALDAV:supported-calendar-data): The attributes
"content-type" and "version" of the CALDAV:calendar-data
XML elements specify a media type supported by the
server for calendar object resources.
Postconditions:
None.
In this example, the client requests the server to
return specific properties of the VEVENT components
referenced by specific URIs. In addition the
DAV:getetag property is also requested and returned as
part of the response. Note that in this example, the
resource at
http://cal.example.com/home/bernard/calendar/mtg1.ics
does not exist, resulting in an error status response.
The CALDAV:free-busy-query REPORT generates a VFREEBUSY
component containing free busy information for all the
calendar object resources targeted by the request and
which have the CALDAV:read-free-busy or DAV:read privilege
granted to the current user.
Only VEVENT components without a TRANSP property or with the
TRANSP property set to "OPAQUE", and VFREEBUSY components
SHOULD be considered to generate the free busy time information.
In the case of VEVENT components, the free or busy time type
(FBTYPE) of the FREEBUSY properties in the returned VFREEBUSY
component SHOULD be derived from the value of the TRANSP and
STATUS properties as outlined in the table below:
Duplicate busy time periods with the same FBTYPE parameter
value SHOULD NOT be specified in the returned VFREEBUSY
component. Servers SHOULD coalesce consecutive or overlapping
busy time period of the same type. Busy time periods with
different FBTYPE parameter values MAY overlap.
Support for the CALDAV:free-busy-query REPORT is REQUIRED.
Marshalling:
The request body MUST be a CALDAV:free-busy-query XML
element (see ,
which MUST contain exactly one CALDAV:time-range XML
element, as defined in .
The request MAY include a Depth header. If no Depth header
is included, Depth:0 is assumed.
The response body for a successful request MUST be an
iCalendar object that contains exactly one VFREEBUSY
component that describes the busy time intervals for the
calendar object resources containing VEVENT or VFREEBUSY
components that satisfy the Depth value and for which the
current user is at least granted the CALDAV:read-free-busy
privilege. If no calendar object resource are found to
satisfy these conditions a VFREEBUSY component with no
FREEBUSY property MUST be returned. This REPORT only
returns busy time information. Free time information can
be inferred from the returned busy time information.
If the current user is not granted the DAV:read privilege
on the Request-URI, the CALDAV:free-busy-query REPORT
request MUST fail and return a 404 (Not Found) status
value. This restriction will prevent users from discovering
URLs of resources for which they are only granted the
CALDAV:read-free-busy privilege.
Preconditions:
None.
Postconditions:
(DAV:number-of-matches-within-limits): The number of matching
calendar object resources must fall within server-specific,
predefined limits. For example, this postcondition might fail
if the specified CALDAV:time-range would cause an extremely
large number calendar object resources to be considered to
compute the response.
In this example, the client requests the server to
return free busy information on the calendar collection
/home/bernard/calendar/, between 9:00 AM and 5:00 PM on 2nd
September 2004. The server responds indicating three
busy time intervals of one hour, two hours and 30 minutes
during the course of the time interval being examined.
There are a number of actions clients can take which will be
legal (the server will not return errors) but which can degrade
interoperability with other client implementations accessing
the same data. For example, a recurrence rule could be replaced
with a set of recurrence dates, a single recurring event could
be replaced with a set of independent resources to represent
each recurrence, or the start/end time values can be translated
from the original timezone to another timezone. Although this
advice amounts to iCalendar interoperability best practices and
is not limited only to CalDAV usage, interoperability problems are
likely to be more evident in CalDAV use cases.
WebDAV already provides functionality required to synchronize a
collection or set of collections, make changes offline, and a
simple way to resolve conflicts when reconnected. ETags
are the key to making this work, but these are not required of
all WebDAV servers. Since offline functionality is more
important to calendar applications than to some other WebDAV
applications, CalDAV servers MUST support ETags as specified
in .
The REPORTs provided in CalDAV can be used by clients to
optimize their performance in terms of network bandwidth
usage, and resource consumption on the local client machine.
Both are certainly major considerations for mobile or handheld
devices with limited capacity, but they are also relevant to
desktop client applications in cases where the calendar
collections contain large amounts of data.
Typically clients present calendar data to users in
views that span a finite time interval, so whenever
possible clients should only retrieve calendar components
from the server using CALDAV:calendar-query REPORT combined
with a CALDAV:time-range element to limit the set of
returned components to just those needed to populate the
current view.
Typically in a calendar, historical data (events, to-dos
etc. that have completed prior to the current date) do
not change, though they may be deleted. As a result, a
client can speed up the synchronization process by only
considering data for the present time and the future
up to a reasonable limit (e.g., one week, one month). If
the user then tries to examine a portion of the
calendar outside of the range that has been
synchronized, the client can perform another
synchronization operation on the new time interval being
examined. This "just-in-time" synchronization can
minimize bandwidth for common user interaction
behaviors.
If a client wants to support calendar data synchronization,
as opposed to downloading calendar data each time it is needed,
it needs to cache the calendar object resource's URI and ETag
along with the actual calendar data. While the URI remains
static for the lifetime of the calendar object resource, the
ETag will change with each successive change to the calendar
object resource. Thus to synchronize a local data cache with
the server, the client can first fetch the URI/ETag pairs for
the time interval being considered, and compare those results
with the cached data. Any cached component whose ETag differs
from that on the server needs to be refreshed.
In order to properly detect the changes between the server and
client data, the client will need to keep a record of which
calendar object resources have been created, changed or deleted
since the last synchronization operation so that it can reconcile
those changes with the data on the server.
Here's an example of how to do that:
The client issues a CALDAV:calendar-query REPORT request
for a specific time range, and asks for only the
DAV:getetag property to be returned:
The client then uses the results to determine which calendar
object resources have changed, been created or deleted on
the server and how those relate to locally cached calendar
object resources that may have changed, been created or
deleted. If the client determines that there are calendar
object resources on the server that need to be fetched,
the client issues a CALDAV:calendar-multiget REPORT request
to fetch their calendar data:
Clients may not need all the calendar properties of a calendar
object resource when presenting information to the user. Since
some calendar property values can be large (e.g., ATTACH or
ATTENDEE) clients can choose to restrict the
calendar properties to be returned in a calendaring REPORT
request to those it knows it will use.
However, if a client needs to make a change to a calendar object
resource, it can only change the entire calendar object resource
via a PUT request. There is currently no way to incrementally make
a change to a set of calendar properties of a calendar object
resource. As a result the client will have to get the entire
calendar object resource that is being changed.
WebDAV locks can be used to prevent two clients modifying the
same resource from either overwriting each others' changes
(though that problem can also be solved by using ETags) or
wasting time making changes that will conflict
with another set of changes. In a multi-user calendar system,
an interactive calendar client could lock an event while the user is
editing the event, and unlock the event when the user finishes
or cancels. Locks can also be used to prevent changes while
data is being reorganized. For example, a calendar client
might lock two calendar collections prior to moving a bunch
of calendar resources from one to another.
Clients are responsible for requesting a lock timeout period that
is appropriate
to the use case. When the user explicitly decides to reserve
a resource and prevent other changes, a long timeout might be
appropriate, but in cases when the client automatically decides
to lock the resource the timeout should be short (and the client
can always refresh the lock should it need to). A short lock
timeout means that if the client is unable to remove the lock,
the other calendar users aren't prevented from making changes.
Much of the time a calendar client (or agent) will discover
a new calendar's location by being provided directly with the
URL. E.g. a user will type his or her own calendar location into
client configuration information, or copy and paste a URL from
email into the calendar application. The client need only confirm
that the URL points to a resource which is a calendar collection.
The client may also be able to browse WebDAV collections to find
calendar collections.
The choice of HTTP URLs means that calendar object resources are
backward compatible with existing software, but does have the
disadvantage that existing software does not usually know to look at
the OPTIONS response to that URL to determine what can be done with it.
This is somewhat of a barrier for WebDAV usage as well as with CalDAV
usage. This specification does not offer a way through this other than
making the information available in the OPTIONS response should this
be requested.
For calendar sharing and scheduling use cases, one might wish to
find the calendar belonging to another user. If the other user has
a calendar in the same repository, that calendar can be found by
using the principal namespace required by WebDAV ACL support.
For other cases, the authors have no universal solution but
implementors can consider whether to use
vCard or
LDAP standards together with
calendar attributes.
Because CalDAV requires servers to support
WebDAV ACL including principal namespaces, and with the
addition of the CALDAV:calendar-home-set property, there are a
couple options for CalDAV clients to find one's own calendar or
another user's calendar.
The DAV:principal-match REPORT is used to query the principal
namespace to find all principals for which a named property
has a value corresponding to the Principal-URL of the current
user. A request for the DAV:principal-match REPORT while
specifying that the DAV:principal-URL property must match the
DAV:principal-URL of the current user is in effect asking "who
am I" or more exactly "what is the identifier for the user
authenticated in this request". The same request can also
include a DAV:prop element naming other properties to return,
so in one request asking for the CALDAV:calendar-home-set
property, a WebDAV client can learn "who am I" and "where are
my calendars". The REPORT request body looks like this:
To find other users calendars, the DAV:principal-property-search
REPORT can be used to filter on some properties and return
others. To search for a calendar owned by a user named "Laurie",
the REPORT request body would look like this:
The server performs a case-sensitive or caseless search for a
matching string subset of "Laurie" within the DAV:displayname
property. Thus, the server might return "Laurie Dusseault",
"Laurier Desruisseaux" or "Wilfrid Laurier" all as matching
DAV:displayname values, and the calendars for each of these.
CalDAV clients MAY create attachments in calendar components either
as inline or external. This section contains some guidelines on
creating and managing attachments.
CalDAV clients MUST support inline attachments as specified in
iCalendar. CalDAV servers MUST
support inline attachments, so clients can rely on being able
to create attachments this way. On the other hand, inline
attachments have some drawbacks:
Servers MAY impose limitations on the size of calendar
object resources (i.e., refusing PUT requests of very
large iCalendar objects).
Servers MAY impose storage quota limitations on calendar
collections (See ).
Any change to a calendar object resource containing an
attachment requires the entire attachment to be
re-uploaded.
Clients synchronizing a changed calendar object resource
have to download the entire calendar object resource even
if the attachment is unchanged.
CalDAV clients MUST support external attachments: if the client
accesses any calendar object resource it MUST be capable of also
accessing the external attachment if one exists. An external
attachment could be:
In a collection in the calendar collection containing
the calendar object resource;
Somewhere else in the same repository that hosts the
calendar collection; or
On an HTTP or FTP server elsewhere.
CalDAV servers MAY provide support for child collections in
calendar collections. CalDAV servers MAY allow the MKCOL
method to create child collections in calendar collections.
Child collections of calendar collections MAY contain any
type of resource except calendar collections which they MUST
NOT contain. Some CalDAV servers won't allow child collections
in calendar collections, and it may be possible on such a
server to discover other locations where attachments can be
stored.
Clients are entirely responsible for maintaining reference
consistency with calendar components that link to external
attachments. A client deleting a calendar component with an
external attachment might therefore also delete the attachment
if that's appropriate, however appropriateness can be very hard
to determine. A new component might easily reference some
pre-existing Web resource which is intended to have
independent existence from the calendar component (the
"attachment" could be a major proposal to be discussed
in a meeting, for instance). Best practices will probably
emerge and should probably be documented but for now clients
should be wary of engaging in aggressive "cleanup" of external
attachments. A client could involve the user in making
decisions about removing unreferenced documents, or a client
could be conservative in only deleting attachments it had
created.
Also, clients are responsible for consistency of permissions
when using external attachments. One reason for servers to
support the storage of attachments within child collections of
calendar collections is that ACL inheritance might make it
easier to grant the same permissions to attachments that are
granted on the calendar collection. Otherwise, it can be very
difficult to keep permissions synchronized. With attachments
stored on separate repositories, it can be impossible to keep
permissions consistent -- the two repositories may not support
the same permissions or have the same set of principals. Some
systems have used tickets or other anonymous access control
mechanisms to provide partially satisfactory solutions to these
kinds of problems.
Note that all CalDAV calendar collections (including those
which the user might treat as public or group calendars) can
contain alarm information on events and to-dos. Users can
synchronize a calendar between multiple devices and decide
to have alarms execute on a different device than the device
that created the alarm. Not all alarm action types are completely
interoperable (e.g., those which name a sound file to play).
When the action is "AUDIO", and the client is configured to
execute the alarm, the client SHOULD play the suggested
sound if it's available or play another sound, but SHOULD NOT
rewrite the alarm just to replace the suggested sound with
a sound that's locally available.
When the action is "DISPLAY", and the client is configured to
execute the alarm, the client SHOULD execute a display alarm by
displaying either according to the suggested description or
some reasonable replacement, but SHOULD NOT rewrite the alarm
for its own convenience.
When the action is "EMAIL", and the client is incapable of
sending email, it SHOULD ignore the alarm but MUST continue
to synchronize the alarm itself.
This specification makes no recommendations about executing
alarm of type PROCEDURE except to note that clients are
advised to take care to avoid creating security holes by
executing these.
Non-interoperable alarm information (e.g., should somebody define
a color to be used in a display alarm) should be put in non-standard
properties inside the VALARM component in order to keep the basic
alarm usable on all devices.
Clients that allow changes to calendar object resources MUST
synchronize the alarm data that already exists in the resources.
Clients MAY execute alarms that are downloaded in this fashion,
possibly based on user preference. If a client is only doing
read operations on a calendar and there is no risk of losing
alarm information, then the client MAY discard alarm information.
This specification makes no attempt to provide multi-user alarms
on group calendars or to find out who an alarm is intended for.
Addressing those issues might require extensions to iCalendar,
for example to store alarms per-user or indicate which user a
VALARM was intended for. In the meantime, clients might maximize
interoperability by generally not uploading alarm information to
public, group or resource calendars.
calendar
urn:ietf:params:xml:ns:caldav
Specifies the resource type of a calendar collection.
See .
mkcalendar
urn:ietf:params:xml:ns:caldav
Specifies a request that lists the WebDAV property values
to be set for a calendar collection resource.
See .
mkcalendar-response
urn:ietf:params:xml:ns:caldav
Specifies a response body for a successful MKCALENDAR request.
See .
calendar-query
urn:ietf:params:xml:ns:caldav
Defines a REPORT for querying calendar object resources.
See .
calendar-data
urn:ietf:params:xml:ns:caldav
Used to
(1) specify a supported media type for
calendar object resources when nested in the
CALDAV:supported-calendar-data property;
(2) specify which parts of a calendar object resource
should be returned by a given calendaring REPORT; and
(3) specify the content of a calendar object resource
in a response to a calendaring REPORT.
When nested in the CALDAV:supported-calendar-data property,
the CALDAV:calendar-data XML element specifies a media type
supported by the CalDAV server for calendar object resources.
When used in a calendaring REPORT request, the
CALDAV:calendar-data XML element specifies which parts
of calendar object resources need to be returned in the
response. If the CALDAV:calendar-data XML element doesn't
contain any CALDAV:comp element, calendar object resources
will be returned in their entirety.
Finally, when used in a calendaring REPORT response, the
CALDAV:calendar-data XML element specifies the content of
a calendar object resource. Given that XML parsers normalizes
the two-character sequence CRLF (US-ASCII decimal 13 and
US-ASCII decimal 10) to a single LF character (US-ASCII
decimal 10), the CR character (US-ASCII decimal 13) MAY be
omitted in calendar object resources specified in the
CALDAV:calendar-data XML element. Furthermore, calendar
object resources specified in the CALDAV:calendar-data XML
element MAY be invalid per their media type specification
if the CALDAV:calendar-data XML element part of the
calendaring REPORT request did not specify required properties
(e.g., UID, DTSTAMP, etc.) or specified a CALDAV:prop XML
element with the "novalue" attribute set to "yes".
The CALDAV:calendar-data XML element is specified in
requests and responses inside the DAV:prop XML element
as if it were a WebDAV property. However, the
CALDAV:calendar-data XML element is not a WebDAV
property and as such it is not returned in PROPFIND
responses nor used in PROPPATCH requests.
comp
urn:ietf:params:xml:ns:caldav
Defines which component types to return.
The name value is a calendar component name
(e.g., "VEVENT").
The CALDAV:prop and CALDAV:allprop elements have
the same name as the DAV:prop and DAV:allprop
elements defined in .
However, the CALDAV:prop and CALDAV:allprop element
are defined in the "urn:ietf:params:xml:ns:caldav"
namespace instead of the "DAV:" namespace.
allcomp
urn:ietf:params:xml:ns:caldav
Specifies that all components shall be returned.
The CALDAV:allcomp XML element can be used when the
client wants all types of components returned by a
calendaring REPORT request.
allprop
urn:ietf:params:xml:ns:caldav
Specifies that all properties shall be returned.
The CALDAV:allprop XML element can be used when the client
wants all properties of components returned by a
calendaring REPORT request.
The CALDAV:allprop element has the same name as the
DAV:allprop element defined in .
However, the CALDAV:allprop element is defined in the
"urn:ietf:params:xml:ns:caldav" namespace instead of
the "DAV:" namespace.
prop
urn:ietf:params:xml:ns:caldavDefines which
properties to return in the
response.The "name"
attribute specifies the name of the
calendar property to return (e.g.,
"ATTENDEE"). The "novalue" attribute
can be used by clients to request that
the actual value of the property not be
returned (if the "novalue" attribute is
set to "yes"). In that case the server
will return just the iCalendar property
name and any iCalendar parameters and a
trailing ":" without the subsequent
value data.
The CALDAV:prop element has the same name as the
DAV:prop element defined in .
However, the CALDAV:prop element is defined in the
"urn:ietf:params:xml:ns:caldav" namespace instead of
the "DAV:" namespace.
expand
urn:ietf:params:xml:ns:caldav
Forces the server to expand recurring components
into individual recurrence instances.
The CALDAV:expand XML element specifies that for
a given calendaring REPORT request the server MUST
expand the recurrence set into calendar components
that define exactly one recurrence instance and MUST
return only those whose scheduled time intersect a
specified time range.
The "start" attribute specifies the inclusive start
of the time range, and the "end" attribute specifies
the non-inclusive end of the time range. Both
attributes are specified as date with UTC time value.
The server MUST use the same logic as defined for
CALDAV:time-range to determine if a recurrence
instance intersects the specified time range.
The returned calendar components MUST NOT use
recurrence properties (i.e., EXDATE, EXRULE, RDATE
and RRULE) and MUST NOT have reference to or include
VTIMEZONE components. Date and local time with reference
to time zone information MUST be converted into date
with UTC time.
limit-recurrence-set
urn:ietf:params:xml:ns:caldav
Specifies a time range to limit the set of "overridden
components" returned by the server.
The CALDAV:limit-recurrence-set XML element specifies that
for a given calendaring REPORT request the server MUST only
return the "master component" as well as the "overridden
components" that specify one or more recurrence instances
whose current scheduled time or original scheduled time
intersect a specified time range.
The "start" attribute specifies the inclusive start
of the time range, and the "end" attribute specifies
the non-inclusive end of the time range. Both
attributes are specified as date with UTC time value.
The server MUST use the same logic as defined for
CALDAV:time-range to determine if the current or
original scheduled time of an "overridden"
recurrence instance intersect the specified time
range.
Overridden components that have a RANGE parameter on their
RECURRENCE-ID property may specify one or more instances
in the recurrence set, and some of those instances may
fall within the specified time range, or may have
originally fallen within the specified time range prior
to being overridden. If that is the case, the overridden
component MUST be included in the results as it has a
direct impact on the interpretation of instances within
the specified time range.
limit-freebusy-set
urn:ietf:params:xml:ns:caldav
Specifies a time range to limit the set of FREEBUSY
values returned by the server.
The CALDAV:limit-freebusy-set XML element specifies
that for a given calendaring REPORT request the server
MUST only return the FREEBUSY property values of a
VFREEBUSY component that intersect a specified time
range.
The "start" attribute specifies the inclusive start
of the time range, and the "end" attribute specifies
the non-inclusive end of the time range. Both
attributes are specified as "date with UTC time" value.
The server MUST use the same logic as defined for
CALDAV:time-range to determine if a FREEBUSY property
value intersect the specified time range.
filter
urn:ietf:params:xml:ns:caldav
Specifies a filter to limit the set of calendar
components returned by the server.
The CALDAV:filter XML element specifies the search
filter used to limit the calendar components returned
by a calendaring REPORT request.
comp-filter
urn:ietf:params:xml:ns:caldav
Specifies search criteria on calendar components.
The CALDAV:comp-filter XML element specifies the
queried calendar component type (e.g., "VEVENT").
A calendar object resource is said to match a
CALDAV:comp-filter if it contains calendar components of
the type specified by the "name" attribute, and that it
contains at least one recurrence instance scheduled to
overlap a given time range if a CALDAV:time-range XML
element is specified, and that any CALDAV:prop-filter
and CALDAV:comp-filter child elements also matches.
prop-filter
urn:ietf:params:xml:ns:caldav
Specifies search criteria on calendar properties.
The CALDAV:prop-filter XML element specifies a
search criteria on a specific calendar property
(e.g., CATEGORIES) in the scope of a given
CALDAV:comp-filter. A calendar component is said
to match a CALDAV:prop-filter if it defines the
property specified by the "name" attribute, and
that it matches the CALDAV:time-range or
CALDAV:text-match conditions if specified, and
that any CALDAV:param-filter child elements also
matches.
param-filter
urn:ietf:params:xml:ns:caldav
Limits the search to specific parameter values.
The CALDAV:param-filter XML element specifies a
search criteria on a specific calendar property
parameter (e.g., PARTSTAT) in the scope of a
given CALDAV:prop-filter. A calendar property
is said to match a CALDAV:param-filter if it
defines the parameter specified by the "name"
attribute, and that it matches the
CALDAV:text-match condition if specified.
text-match
urn:ietf:params:xml:ns:caldavSpecifies a substring
match on a property or parameter value.
The CALDAV:text-match XML element specifies text used
for a substring match against the property or parameter
value specified in a calendaring REPORT request.
The "caseless" attribute indicates whether the match
is case-sensitive (value set to "no") or
case-insensitive (value set to "yes"). The default
value is server-specified. Caseless matching SHOULD
be implemented as defined in section 5.18
of the Unicode Standard ().
Support for the "caseless" attribute is optional.
A server should respond with a status of 422 if it
is used but cannot be supported.
timezone
urn:ietf:params:xml:ns:caldav
Specifies the time zone component...
The CALDAV:timezone XML element specifies that for a
given calendaring REPORT request the server MUST rely
on the specified VTIMEZONE component instead of the
CALDAV:calendar-timezone property of the calendar
collection in which the calendar object resource is
contained to resolve "date" values and "date with local
time" values (i.e., floating time) to "date with UTC time"
values. The server will require this information to
determine if a calendar component scheduled with "date"
values or "date with local time" values intersect a
CALDAV:time-range specified in a CALDAV:calendar-query
REPORT.
time-range
urn:ietf:params:xml:ns:caldav
Specifies a time range to limit the set of calendar
components returned by the server.
The CALDAV:time-range XML element specifies that for a
given calendaring REPORT request the server MUST only
return the calendar object resources that, depending
on the context, have a component or property or
parameter whose value intersect a specified time range.
The "start" attribute specifies the inclusive start
of the time range, and the "end" attribute specifies
the non-inclusive end of the time range. Both attributes
are specified as "date with UTC time" value.
While the "start" and "end" attributes are not required
to allow time ranges opened at one end, at least one of
them MUST be specified in the CALDAV:time-range element.
A VEVENT component overlaps a given time range if:
A VEVENT component with no DTSTART and DTEND
properties does not overlap any time range.
A VTODO component overlaps a given time range if:
A VTODO component with no DTSTART and DUE
properties does not overlap any time range.
A VJOURNAL component overlaps a given time range if:
A VJOURNAL component with no DTSTART property
does not overlap any time range.
A VFREEBUSY component overlaps a given time range if
for any of its FREEBUSY property value the following
condition holds:
A VFREEBUSY component with no FREEBUSY property
does not overlap any time range.
A VALARM component overlaps a given time range if:
A VALARM component can be defined such that it
triggers repeatedly. Such a VALARM component is
said to overlap a given time range if at least
one of its trigger overlap the time range.
The calendar properties COMPLETED, CREATED, DTSTAMP
and LAST-MODIFIED overlaps a given time range
The semantic of CALDAV:time-range is not defined
for any other calendar properties.
calendar-multiget
urn:ietf:params:xml:ns:caldav
CalDAV REPORT used to retrieve specific calendar
object resources.
See .
free-busy-query
urn:ietf:params:xml:ns:caldav
CalDAV REPORT used to generate a
VFREEBUSY to determine busy time over a specific
time range.
See .
CalDAV allows internationalized strings to be stored and
retrieved for the description of calendar collections
(see ).
HTTP protocol transactions are sent in the clear over the
network unless protection from snooping is negotiated. This
can be accomplished by use of TLS as defined in
.
In particular, HTTP Basic authentication MUST NOT be used
unless TLS is in effect.
Servers MUST take adequate precautions to ensure malicious
clients cannot consume excessive server resources (CPU, memory,
disk, etc.) through carefully crafted reports. For example, a
client could upload an event with a recurrence rule that
specifies a recurring event occurring every second for the next
100 years which would result in approximately 3 x 10^9
instances! A REPORT that asks for recurrences to be expanded
over that range would likely constitute a denial-of-service
attack on the server.
Security considerations described in
iCalendar and
iTIP are also applicable to CalDAV.
Beyond these, CalDAV does not raise any security considerations
that are not present in HTTP and
WebDAV , ,
, as discussed in those documents.
This document uses one new URN to identify a new XML namespace.
The URN conforms to a registry mechanism described in
.
Registration request for the CalDAV namespace: URI: urn:ietf:params:xml:ns:caldav Registrant Contact: See the "Author's Address" section of
this document. XML: None. Namespace URIs do not represent an XML
specification.
The authors would like to thank the following individuals
for contributing their ideas and support for writing this
specification: Michael Arick, Mario Bonin, Chris Bryant,
Scott Carr, Mike Douglass, Helge Hess, Dan Mosedale,
Kervin L. Pierre, Julian F. Reschke, Mike Shaver,
Simon Vaillancourt, Wilfredo Sanchez Vega and
Jim Whitehead.
The authors would also like to thank the Calendaring and
Scheduling Consortium for advice with this specification,
and for organizing interoperability testing events to help
refine it.
Key words for use in RFCs to Indicate Requirement LevelsHarvard University1350 Mass. Ave.CambridgeMA 02138- +1 617 495 3864sob@harvard.edu
General
keyword
In many standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized. This document defines these words as they should be
interpreted in IETF documents. Authors who follow these guidelines
should incorporate this phrase near the beginning of their document:
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
RFC 2119.
Note that the force of these words is modified by the requirement
level of the document in which they are used.
The TLS Protocol Version 1.0Certicomtdierks@certicom.comCerticomcallen@certicom.comThis document specifies Version 1.0 of the Transport Layer Security (TLS) protocol. The TLS protocol provides communications privacy over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery.Internet Calendaring and Scheduling Core Object Specification (iCalendar)Lotus Development Corporation6544 Battleford DriveRaleighNC27613-3502USA+1-919-676-9515+1-919-676-9564Frank_Dawson@Lotus.comhttp://home.earthlink.net/~fdawsonMicrosoft CorporationOne Microsoft WayRedmondWA98052-6399USA+1-425-936-5522+1-425-936-7329deriks@Microsoft.com
Applications
calendaringschedulingPIM
There is a clear need to provide and deploy interoperable calendaring
and scheduling services for the Internet. Current group scheduling
and Personal Information Management (PIM) products are being extended
for use across the Internet, today, in proprietary ways. This memo
has been defined to provide the definition of a common format for
openly exchanging calendaring and scheduling information across the
Internet.
This memo is formatted as a registration for a MIME media type per
. However, the format in this memo is equally applicable
for use outside of a MIME message content type.
The proposed media type value is 'text/calendar'. This string would
label a media type containing calendaring and scheduling information
encoded as text characters formatted in a manner outlined below.
This MIME media type provides a standard content type for capturing
calendar event, to-do and journal entry information. It also can be
used to convey free/busy time information. The content type is
suitable as a MIME message entity that can be transferred over MIME
based email systems, using HTTP or some other Internet transport. In
addition, the content type is useful as an object for interactions
between desktop applications using the operating system clipboard,
drag/drop or file systems capabilities.
This memo is based on the earlier work of the vCalendar specification
for the exchange of personal calendaring and scheduling information.
In order to avoid confusion with this referenced work, this memo is
to be known as the iCalendar specification.
This memo defines the format for specifying iCalendar object methods.
An iCalendar object method is a set of usage constraints for the
iCalendar object. For example, these methods might define scheduling
messages that request an event be scheduled, reply to an event
request, send a cancellation notice for an event, modify or replace
the definition of an event, provide a counter proposal for an
original event request, delegate an event request to another
individual, request free or busy time, reply to a free or busy time
request, or provide similar scheduling messages for a to-do or
journal entry calendar component. The iCalendar Transport-indendent
Interoperability Protocol (iTIP) defined in is one such
scheduling protocol.
iCalendar Transport-Independent Interoperability Protocol (iTIP) Scheduling Events, BusyTime, To-dos and Journal EntriesMicrosoft CorporationOne Microsoft WayRedmondWA98052-6399USA+1-425-936-9277+1-425-936-8019stevesil@Microsoft.comNetscape Communications Corporation501 East Middlefield RoadMountainViewCA94043USA+1-650-937-2378+1-650-937-2103sman@netscape.comLotus Development Corporation6544 Battleford DriveRaleighNC27613-3502USA+1-919-676-9515+1-919-676-9564Frank_Dawson@Lotus.comhttp://home.earthlink.net/~fdawsonOn Technology, Inc.434 Fayetteville St.Mall, Two Hannover SquareSuite 1600RaleighNC27601+1-919-890-4036+1-919-890-4100rhopson@on.com
Applications
calendaringscheduling
This document specifies how calendaring systems use iCalendar objects
to interoperate with other calendar systems. It does so in a general
way so as to allow multiple methods of communication between systems.
Subsequent documents specify interoperable methods of communications
between systems that use this protocol.
The document outlines a model for calendar exchange that defines both
static and dynamic event, to-do, journal and free/busy objects.
Static objects are used to transmit information from one entity to
another without the expectation of continuity or referential
integrity with the original item. Dynamic objects are a superset of
static objects and will gracefully degrade to their static
counterparts for clients that only support static objects.
This document specifies an Internet protocol based on the iCalendar
object specification that provides scheduling interoperability
between different calendar systems. The Internet protocol is called
the "iCalendar Transport-Independent Interoperability Protocol
(iTIP)".
iTIP complements the iCalendar object specification by adding
semantics for group scheduling methods commonly available in current
calendar systems. These scheduling methods permit two or more
calendar systems to perform transactions such as publish, schedule,
reschedule, respond to scheduling requests, negotiation of changes or
cancel iCalendar-based calendar components.
iTIP is defined independent of the particular transport used to
transmit the scheduling information. Companion memos to iTIP provide
bindings of the interoperability protocol to a number of Internet
protocols.
HTTP Extensions for Distributed Authoring -- WEBDAVMicrosoft CorporationOne Microsoft WayRedmondWA98052-6399yarong@microsoft.comDept. Of Information and Computer Science,
University of California, IrvineIrvineCA92697-3425ejw@ics.uci.eduNetscape685 East Middlefield RoadMountain ViewCA94043asad@netscape.comNovell1555 N. Technology WayM/S ORM F111OremUT84097-2399srcarter@novell.comNovell1555 N. Technology WayM/S ORM F111OremUT84097-2399dcjensen@novell.com
This document specifies a set of methods, headers, and content-types
ancillary to HTTP/1.1 for the management of resource properties,
creation and management of resource collections, namespace
manipulation, and resource locking (collision avoidance).
Hypertext Transfer Protocol -- HTTP/1.1Department of Information and Computer ScienceUniversity of California, IrvineIrvineCA92697-3425+1(949)824-1715fielding@ics.uci.eduWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682jg@w3.orgCompaq Computer CorporationWestern Research Laboratory250 University AvenuePalo AltoCA94305mogul@wrl.dec.comWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682frystyk@w3.orgXerox CorporationMIT Laboratory for Computer Science, NE43-3563333 Coyote Hill RoadPalo AltoCA94034masinter@parc.xerox.comMicrosoft Corporation1 Microsoft WayRedmondWA98052paulle@microsoft.comWorld Wide Web ConsortiumMIT Laboratory for Computer Science, NE43-356545 Technology SquareCambridgeMA02139+1(617)258-8682timbl@w3.org
The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypermedia information
systems. It is a generic, stateless, protocol which can be used for
many tasks beyond its use for hypertext, such as name servers and
distributed object management systems, through extension of its
request methods, error codes and headers . A feature of HTTP is
the typing and negotiation of data representation, allowing systems
to be built independently of the data being transferred.
HTTP has been in use by the World-Wide Web global information
initiative since 1990. This specification defines the protocol
referred to as "HTTP/1.1", and is an update to RFC 2068 .
HTTP Over TLSThis memo describes how to use Transport Layer Security (TLS) to secure Hypertext Transfer Protocol (HTTP) connections over the Internet. This memo provides information for the Internet community. Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)Rational Software20 Maguire RoadLexingtonMA02421USgeoffrey.clemm@rational.comIBM3039 CornwallisResearch Triangle ParkNC27709USjamsden@us.ibm.comIBMHursley ParkWinchesterS021 2JNUKtim_ellison@uk.ibm.comMicrosoftOne Microsoft WayRedmondWA90852USckaler@microsoft.comUC Santa Cruz, Dept. of Computer Science1156 High StreetSanta CruzCA95064USejw@cse.ucsc.edu
This document specifies a set of methods, headers, and resource types
that define the WebDAV (Web Distributed Authoring and Versioning)
versioning extensions to the HTTP/1.1 protocol. WebDAV versioning
will minimize the complexity of clients that are capable of
interoperating with a variety of versioning repository managers, to
facilitate widespread deployment of applications capable of utilizing
the WebDAV Versioning services. WebDAV versioning includes automatic
versioning for versioning-unaware clients, version history
management, workspace management, baseline management, activity
management, and URL namespace versioning.
The IETF XML RegistryThis document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. Web Distributed Authoring and Versioning (WebDAV) Access Control ProtocolIBM20 Maguire RoadLexingtonMA02421geoffrey.clemm@us.ibm.comgreenbytes GmbHSalzmannstrasse 152MuensterNW48159Germanyjulian.reschke@greenbytes.deOracle Corporation500 Oracle ParkwayRedwood ShoresCA94065eric.sedlar@oracle.comU.C. Santa Cruz, Dept. of Computer Science1156 High StreetSanta CruzCA95064ejw@cse.ucsc.edu
This document specifies a set of methods, headers, message bodies,
properties, and reports that define Access Control extensions to the
WebDAV Distributed Authoring Protocol. This protocol permits a client to
read and modify access control lists that instruct a server whether to
allow or deny operations upon a resource (such as HyperText Transfer
Protocol (HTTP) method invocations) by a given principal. A lightweight
representation of principals as Web resources supports integration of a
wide range of user management repositories. Search operations allow
discovery and manipulation of principals using human names.
Extensible Markup Language (XML) 1.0 (Third Edition)The Unicode Standard, Version 4.0The Unicode ConsortiumLightweight Directory Access Protocol (v3)Critical Angle Inc.4815 W Braker Lane #502-385AustinTX 78759USA+1 512 372-3160M.Wahl@critical-angle.comNetscape Communications Corp.501 E. Middlefield Rd.MS MV068Mountain ViewCA 94043USA+1 650 937-3419howes@netscape.comIsode LimitedThe DomeThe SquareRichmondTW9 1DTUK+44-181-332-9091S.Kille@isode.com
Applications
LDAPITU directory service protocoldirectorylightweight directory access protocol
This RFC contained boilerplate in this section which has been moved
to the RFC2223-compliant unnumbered section "Status of this Memo."
This document describes a directory access protocol that provides
both read and update access. Update access requires secure
authentication, but this document does not mandate implementation of
any satisfactory authentication mechanisms.
In accordance with RFC 2026, section 4.4.1, this specification is
being approved by IESG as a Proposed Standard despite this
limitation, for the following reasons:
a. to encourage implementation and interoperability testing of
these protocols (with or without update access) before they
are deployed, and
b. to encourage deployment and use of these protocols in read-only
applications. (e.g. applications where LDAPv3 is used as
a query language for directories which are updated by some
secure mechanism other than LDAP), and
c. to avoid delaying the advancement and deployment of other Internet
standards-track protocols which require the ability to query, but
not update, LDAPv3 directory servers.
Readers are hereby warned that until mandatory authentication
mechanisms are standardized, clients and servers written according to
this specification which make use of update functionality are
UNLIKELY TO INTEROPERATE, or MAY INTEROPERATE ONLY IF AUTHENTICATION
IS REDUCED TO AN UNACCEPTABLY WEAK LEVEL.
Implementors are hereby discouraged from deploying LDAPv3 clients or
servers which implement the update functionality, until a Proposed
Standard for mandatory authentication in LDAPv3 has been approved and
published as an RFC.
vCard MIME Directory ProfileLotus Development Corporation6544 Battleford DriveRaleighNC 27613USA+1-919-676-9515frank_dawson@lotus.comNetscape Communications Corp.501 East Middlefield Rd.Mountain ViewCA 94041USA+1.415.937.3419howes@netscape.com
Applications
MIMEaudiocontent-typedirectorymultipurpose internet mail extensions
This memo defines the profile of the MIME Content-Type for
directory information for a white-pages person object, based on a
vCard electronic business card. The profile definition is independent
of any particular directory service or protocol. The profile is
defined for representing and exchanging a variety of information
about an individual (e.g., formatted and structured name and delivery
addresses, email address, multiple telephone numbers, photograph,
logo, audio clips, etc.). The directory information used by this
profile is based on the attributes for the person object defined in
the X.520 and X.521 directory services recommendations. The profile
also provides the method for including a representation of a
white-pages directory entry within the MIME Content-Type defined by
the document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this
document are to be interpreted as described in .
Calendar Attributes for vCard and LDAPXpertSite.ComISOCORLotusWhen scheduling a calendar entity, such as an event, it is a prerequisite that an organizer has the calendar address of each attendee that will be invited to the event. Additionally, access to an attendee's current "busy time" provides an a priori indication of whether the attendee will be free to participate in the event.In order to meet these challenges, a calendar user agent (CUA) needs a mechanism to locate (URI) individual user's calendar and free/busy time.This memo defines three mechanisms for obtaining a URI to a user's calendar and free/busy time. These include:
- Manual transfer of the information;
- Personal data exchange using the vCard format; and
- Directory lookup using the LDAP protocol.Quota and Size Properties for DAV CollectionsWebDAV servers are frequently deployed with quota (size) limitations. This document discusses the properties and minor behaviors needed for clients to interoperate with quota (size) implementations on WebDAV repositories.
The following table extends the WebDAV Method Privilege
Table specified in Appendix B of .
METHODPRIVILEGESMKCALENDARDAV:bindREPORTDAV:read or CALDAV:read-free-busy
(on all referenced resources)
This appendix shows the calendar object resources contained in
the calendar collections queried in the examples throughout
this document.
The content of each calendar collection is being shown as
it would be returned to the following CALDAV:calendar-query
REPORT request:
[TBD]
Numerous editorial changes.
Removed the CALDAV:is-defined XML element.
Removed section on privilege aggregation.
Renamed the CALDAV:expand-recurrence-set XML element
to CALDAV:expand and clarified the server behavior.
Renamed the CALDAV:calendar-component-restriction-set
XML element to CALDAV:supported-calendar-component-set.
Renamed the CALDAV:calendar-restrictions XML element
to CALDAV:supported-calendar-data.
Renamed some preconditions as "success conditions" instead
of "failure causes". For instance, the precondition
CALDAV:calendar-collection-location-bad has been renamed
to CALDAV:calendar-collection-location-ok.
Reordered some sections.
Clarified the definition of CALDAV:time-range to specify
that a repeating VALARM component is said to intersect a
given time range if at least one of its trigger intersect
the time range.
Clarified that calendar object resources stored in
calendar collections MUST NOT specify the iCalendar
METHOD property.
Clarified that CALDAV:calendar-data XML element is not a
WebDAV property even though it is specified in the DAV:prop
XML element in both calendaring REPORT requests and responses.
Clarified CALDAV:limit-recurrence-set with respect
to the RANGE parameter on the RECURRENCE-ID property.
Changed the CALDAV:free-busy-query XML element to
contain exactly one CALDAV:time-range XML element.
Changed many ELEMENT and ATTLIST declarations to
comply with DTD syntax.
Changed XML element CALDAV:calendar-query to allow
new XML element CALDAV:timezone.
Changed the XML elements CALDAV:time-range, CALDAV:expand
and CALDAV:limit-recurrence-set to only allow DATE-TIME
with UTC time values for the "start" and "end"
attributes.
Changed description of CALDAV:limit-recurrence-set to
specify that re-scheduled "overridden" recurrence
instances whose original scheduled time used to overlap
the time range specified by the "start" and "end"
attribute should always be returned in a REPORT
response.
Changed the description of the value of
CALDAV:calendar-data XML element to specify that the
CR character (US-ASCII decimal 13) MAY be omitted in
the iCalendar object specified in this XML element.
Added specific requirements for entity tags support.
Added more preconditions.
Added further guidelines about finding calendars.
Added XML element CALDAV:limit-freebusy-set to
limit the set of FREEBUSY property values
returned in VFREEBUSY components.
Added property CALDAV:calendar-timezone on calendar
collections.
Added XML element CALDAV:timezone to override the
CALDAV:calendar-timezone property for a given
CALDAV:calendar-query REPORT request.
Added text on the conversion of "floating date" and
"floating time" values to date with UTC time values.
Completed internationalization considerations section.
Completed security considerations section.
Removed statement that said that client SHOULD
always request DAV:getetag in calendar REPORTs.Removed redefiniton of DAV:response.Removed XML elements CALDAV:calendar-data-only.Removed resource type CALDAV:calendar-home.Moved the CALDAV:calendar-data element in the
DAV:prop element in requests, and in the
DAV:propstat element in responses.Further defined the request body of MKCALENDAR to
allow clients to set properties at calendar
collection creation time.Renamed CALDAV:calendar-home-URL to
CALDAV:calendar-home-setClarified the fact that calendar collections
may only contain calendar object resources and
ordinary collections.Clarified that calendar REPORTs should only be
applied to calendar object resources contained
in calendar collections.Changed the CALDAV:calendar-component-restriction-set
and CALDAV:calendar-restriction properties to always
be protected.Changed to use existing postcondition
DAV:needs-privileges instead of a new
CALDAV:insufficient-privilege postcondition.Added example for limit-recurrence-set.Added example for expand-recurrence-set.Moved CALDAV:calendar-address-set in the
calendar-schedule draft and renamed it to
CALDAV:calendar-user-address-set.Added guidelines on attachments and alarms.Various editorial changes.Added properties calendar-restrictions and
calendar-component-restriction-set on calendar
collections.Added properties calendar-home-URL and
calendar-address-set on principal resources.Removed property calendar-URL on principal
resources.Added pre- and postconditions to reports.Added new XML elements calendar-data-only and
limit-recurrent-set.Modified calendar-data XML element to support
the attributes content-type and version.Reorganised sections 3, 4, 5 & 6 into two sections and
re-ordered sub-sections.Added comment about client not setting a duplicate
displayname.Removed three CalDAV OPTIONS requests.Changed "authenticated user" to "user" in various places.Rewrote section on calendar object resource restrictions for
better clarity.Reworded section "Recurrence and the Data Model".Removed timezone collection feature.Removed ability for a server to return the
Location header on a successful PUT request.Clarified restrictions on calendar object resources contained in
calendar collections.Added preconditions on PUT in calendar collections.Added informative "Guidelines" section, with information
on locking and how to find calendar collections.Moved "Sychronization Operations" section in the
"Guidelines" section.Removed a lot of non-normative text.Removed property promotion/demotion requirements.Removed calendar-owner and cal-scale properties.Removed 'ical' prefix/text from element names.Relaxed WebDAV Class 2 (locking) requirement to a MAY.Relaxed MKCALENDAR requirement to a SHOULD.Moved the XML Namespace section in the Introduction.Added CALDAV: prefix to CalDAV XML elements in the text.Added CALDAV:calendar-multiget report.Added CALDAV:free-busy-query report.Added CALDAV:calendar-description property.Changed CALDAV:calendar-query-result element name to
CALDAV:calendar-dataAdded description and examples of handling timezones.Added mandatory "start" and "end" attributes to the
CALDAV:expand-recurrence-set element.Added three CalDAV OPTIONS requests.Grouped XML Element declarations in a separate section.Added a note about the HTTP Location response
header.Added report calendar-query.Removed reports calendar-property-search and
calendar-time-range.Removed section on CalDAV and timezones.Added requirement to return ETag on creation.Revised data model to remove sub-collections from
calendar collection.Added informative references section.Removed dependencies on DASL.Removed Calendar Containers (simplification that
doesn't seem to remove much functionality)Added MKCALENDAR to create calendars and all
sub-collectionsAdded cal-scale property to calendarsBasically still adding major sections of content: Defined new field values to the OPTIONS
"DAV:" response headerAdded new resource
propertiesAdded new principal propertiesAdded new SCHEDULE method and related headersAdded new privileges for schedulingAdded section on privileges for calendaring,
extending WebDAV ACL privilege setDefined what to do with unrecognized properties in
the bodies of iCalendar events, with respect to
property promotion/demotion